Write a Java program that reads a word and prints its bigrams substrings. A character bigram is defined as a continuous sequence of two characters in a word. For example, if the user provides the input "rum", the program prints

ru um Hint:

1. set two pointers, one always moves from the beginning of the string and the other moves from i+2, in which i is the current position of the first pointer.

2. print an error message if the input word is less than 2 characters long.

I've been struggling with this program for a few days now. I'm new to coding and an answer would be greatly appreciated.